What to do
Lift and divide June-flowering bearded iris, if you have not done so for the past three or four years. Congested clumps flower less well than they should. Break off the healthiest, fattest pieces of rhizome and replant them so they sit only half submerged but with the roots well anchored.
If necessary, prune old-fashioned shrub roses that will neither have a repeat flowering season later in the summer nor bear hips in autumn. Shorten back flowered shoots to a healthy bud or side shoot. Take out entirely any poor straggly growth and branches that are rubbing against each other.
Summer prune fruit trees by shortening side shoots on plums. Wall-trained pears and apples may also need attention. Shorten lateral growths to allow the sun to ripen fruit.
Mulch runner beans after watering thoroughly to conserve the moisture which this crop needs. Thin kohl rabi plants so that they are no more than 15cm (6in) apart. Thin young beetroot.
What to see
Tours of the garden and state rooms at Buckingham Palace start on 28 August and run until 1 October, but you must book in advance, and soon. You can't do it on your own, but must be part of a group (15-25). Get your friends together (£23 per person) and call 020-7766 7333 or visit royalcollection.org.uk